Open-end textile spinning machines

ABSTRACT

A sliver feeding device for an open-end spinning machine includes a feed roller, an opening roller, and a displaceable feed pedal biased towards the feed roller. A sliver forming nip is formed between a first surface of the feed pedal and the peripheral surface of the feed roller. The feed pedal also has a second surface adjacent the peripheral surface of the opening roller. The device is provided with constraining means associated with the feed pedal to constrain the feed pedal whereby displacement of the feed pedal produces no substantial variation in the minimum clearance between the first surface and the peripheral surface of the open roller.

Elite States Patent [1 1 Croasdale et a1.

[ Aug. 13, 1974 OPEN-END TEXTILE SPINNING MACHINES [75] Inventors: FredCroasdale, Whalley; James William Barnes Clayton, Arnside; Keith Norman,Oswaldtwistle, all of England [73] Assignee: Platt InternationalLimited, Oldham,

England 22 Filed: Mar. 12,1973

21 Appl.N0.: 340,082

[30] Foreign Application Priority Data Mar. 13, 1972 Great Britain11526/72 [52] U.S. Cl. 57/5891, 57/5895 [51] Int. Cl D0lh 1/12 [58]Field of Search 57/58.8958.95

[56] References Cited UNITED STATES PATENTS 3,360,918 1/1968 Doudlebskyet al. 57/5895 3,455,097 7/1969 Rajnoha et al .7 57/5895 3,511,0455/1970 Bures et al 57/5895 X 3,571,859 3/1971 Doudlebsky et a1. 1.57/5895 X 3,680,300 8/1972 Landwekerkamp 57/5895 X 3,695,022 10/1972Landwekrkamp 57/5895 X -1696.604 10/1972 Nozaki et al .7 57/5895 3.728853 4/1973 Schiltknecht 57/5895 Primary Examiner-John W. Huckert-Assistant Examiner-Charles Gorenstein Attorney, Agent, or Firm-Watson,Cole, Grindle & Watson [57] ABSTRACT A sliver feeding device for anopen-end spinning machine includes a feed roller, an opening roller. anda displaceable feed pedal biased towards the feed roller. A sliverforming nip is formed between a first surface of the feed pedal and theperipheral surface of the feed roller. The feed pedal also has a secondsurface adjacent the peripheral surface of the opening roller.

The device is provided with constraining means associated with the feedpedal to constrain the feed pedal whereby displacement of the feed pedalproduces no substantial variation in the minimum clearance between thefirst surface and the peripheral surface of the open roller.

20 Claims, 6 Drawing Figures PATENIEU AUG 1 31974 SHEET 2 0F 2 4 32 3342 my. a

NOVEL PROCESS FOR PREPARATION OF SILVER CHLORIDE POWDER BACKGROUND 1.Field of the Invention The present invention generally relates to themanufacture of silver chloride and, more particularly, to improvementsin a process for preparing silver chloride from metallic silver bycontact with chlorine gas at elevated temperature.

2. Prior Art A conventional method of manufacturing silver chlorideinvolves dissolving silver or silver-containing scrap material in nitricacid and then precipitating silver chloride from the resulting solutionby contacting the solution with sodium chloride or hydrochloride acid orthe like. The thus precipitated silver chloride is then washed anddried. Attempts to manufacture silver chloride by reaction of silverwith chlorine gas at room temperature or somewhat elevated temperatures,such as 500F. have been largely unsuccessful due to the lack of reactionor the slowness of the reaction.

However, a successful process has beenprovided which is more fullydisclosed in US. Pat. No. 3,147,073, issued Sept. 1, 1964 to Kenneth N.Brown for A Process for Preparing Molten Silver Chloride by theControlled Reaction of Chlorine on Charge of Metallic Silver. Saidpatent has been assigned to assignee of the present application. Saidpatent calls for a process for preparing silver chloride which comprisesintroducing a charge of metallic silver into a reaction chamber, heatingthe reaction chamber to a temperature above the melting point of silverchloride but below the melting point'of silver, continuously introducingchlorine gas at a location above the silver into the reaction chamberand continuously withdrawing the resulting molten silver chloride fromthe reaction chamber at a location below the solid silver in thechamber. With such a process silver chloride can be preparedeconomically. However, even though the silver chloride is relativelypure, it is recovered from the process in molten form and must besubjected to further treatment to place it into the desired finishedsize and shape, as by casting or the like.

Historically, substantial amounts of silver chloride in fine particulateform are utilized in industry for such purposes as, for example,photographic processes and the like. A substantial amount of time andeffort and expense is normally incurred in converting silver chloridefrom solid or molten form into finely particulate solid silver chloridepowder. Accordingly, it would be desirable to provide an improvedprocedure for treatment of the product of the described patented processin an economical manner so as to efficiently yield silver chloridegranules of controlled particulate size as an end product.

SUMMARY OF THE INVENTION The present invention satisfies the foregoingneeds. The invention comprises improvements in a process for preparingsilver chloride from solid silver by contacting elevated temperaturewith chlorine gas. The improvements of the process are substantially asset forth in the Abstract above. Such improvements permit pure silverchloride powder or granules to be easily provided from molten silverchloride formed as the end product of the process described andv claimedin US. Pat. No. 3,147,073. The highly purified silver chloride ingranular or powder form is useful for a variety of purposes includingwater purification and the like due to the bactericidal properties ofthe silver chloride. Such silver chloride is also useful in thephotochemical industry, for example, in the preparation of photographicemulsions and the like. The improvements permit the patented process tooperate on an even more economical basis than heretofore, do not involvecomplicated steps or machinery and can be carried out rapidly in asimple controlled manner. Other advantages and details of theimprovements are as set forth in the following detailed description.

DETAILED DESCRIPTION Silver chloride prepared in molten form inaccordance with the process of US. Pat. No. 3,147,073 or similar processis treated in accordance with the present improvements to render it morereadily disintegratable to fine granular or powder form. The process asset forth in US. Pat. No. 3,147,073 comprises heating pure silverbullion in a reaction zone to a temperature below its melting point butabove the melting point of silver chloride and then continuouslyintroducing chlorine gas above the level of the solid silver bullion inthe reaction zone to react therewith to form molten silver chloride.-The molten silver chloride is continuously withdrawn from the reactionzone below the solid silver so that it does not build up and block thereaction between the chlorine and silver.

In accordance with the present invention, the molten silver chloridewhich exits in the above-described process at a temprature substantiallybelow 1 100F., usually at a temperature of about 900F. is heated in aseparate heating zone to at least about 1100F. but below thedecomposition point thereof and preferably, to about 1300F. Highertemperatures are not necessary to achieve the desired results and mayresult in a waste of energy and time due to unnecessary heating. Lowertemperatures are insufficient to achieve the desired results. After themolten silver chloride has been reheated to the indicated temperature itis then dripped or otherwise passed intoa tank or vessel or reservoircontaining water. Preferably, the water is cooled water, at leastinitially, and it is desired that the temperature difference between themolten silver chloride contacting the water and the water be at leastabout l050F. This temperature difference is necessary in order that thedrops of molten silver chloride when solidifying in contact with thewater do so sufficiently rapidly to cause them to be very brittle. Theprocedure of the invention forms brittle flakes of the silver chloridewhich may vary in size but may be, for example, up to about one-half orso along the major axis thereof and irregularly thin.

Should the temperature differential be less than that indicated as aminimum and/or should the temperature of the silver chloride on contactwith the water be'less than about 1 F., insufficient instantaneouscrystallization of the silver chloride occurs upon contact with thewater regardless of the waters temperature. The net result is that thesolidified globs of silver chloride cannot be readily disintegrated in ahammer mill or otherconventional disintegrating device to fine powder orgranular form without considerable difficulty and with considerableenergy expenditure. It should be noted that the temperature differentialand minimum temperature specified are essential to provide a desiredreadily granulatable product in an economical manner.

After the brittle flakes of silver chloride are formed in accordancewith the improvement of the present invention, the flakes are thendisintegrated in a hammer mill or other similar disintegrating device.It is preferred that the disintegration be carried out while the flakesare in dry form. Accordingly, the flakes may be removed from the waterin which the flakes were formed, dried by conventional means such asheating, air blowing and/or the like and then passed to thedisintegrating means for reduction to the desired particle size. Atypical product has been produced which has a silver chloride content of99.5% and which can be readily milled to an average particle size suchthat 100 percent of the particles readily pass through a 60 mesh screen.The brittleness of the flakes assures that the milling operation is veryreadily carried out. Further aspects of the present invention will beapparent from the following specific Examples.

EXAMPLE I A silver ingot weighing 100 pounds is placed in a closedreaction chamber fitted with external heating means, a gas inlet andoutlet above the silver and a bottom liquid drainage outlet. Thereaction chamber is heated to a temperature of about 1300F. whereuponchlorine gas slightly above atmospheric temperature is introduced intothe reaction chamber through the gas inlet, circulates over the topsurface of the silver and exits the chamber through the gas outlet. Theamount of chlorine gas is regulated to be in excess of that utilized inthe reaction with the silver. The reaction is carried out for a periodof about 100 minutes during which time molten silver chloride is formedon the top surface of the silver, drains from the solid silver, collectsin the bottom of the chamber and is removed from the bottom liquidoutlet.

The molten silver chloride at this point has a temperature ofapproximately 900F. and is caused to flow to a separate heating zone inthe form of a furnace and is heated therein to a temperature of about1200F. and at about that temperature is dripped from the furnace intowater in a tank, the water having an average temperature of about 50F.The water greatly exceeds the silver chloride in volume and ismaintained within the temperature range of about 40F. to about 60F. byinflow of fresh cooled water. Brittle flakes of silver chloride arerecovered from the bottom of the tank of water, dried by heating and airblowing and then passed into a hammer mill and therein granulated toabout 60 mesh screen size. The energy computed to be utilized ingranulating this silver chloride is less than about percent thatrequired to granulate silver chloride prepared by the same processexcept for first casting the silver chloride into molds solidifying andthen breaking into small pieces and hammer milling. Accordingly, thepresent process and its improvements represent a substantial advance inthe art.

ample l above are carried out except that the procedure is continuous.Thus, there is a continuous removal of molten silver chloride from thereaction chamber,

continuous passage of that molten silver chloride to a heating zone,continuous removal of molten silver chloride from the heating zone atabout 1200F. and continuous flowing of the thus-heated molten silverchloride in droplet form into the vat of water. Removal of formed flakesof silver chloride therefrom for hammer milling disintegration iscarried out periodically. The same improved results are obtained as arespecified for Example I.

Parallel runs are carried out in accordance with the process andimprovements set forth in Example I, but substituting reheatingtemperatures of l lOOF., 1300F. and no reheating but merely the exittemperature of 900F. Results indicate that the silver chloride flakesproduced utilizing a reheat temperature of llO0F. and 1300F. areequivalent in properties, in cluding easy granulation, to the product ofExample I. However, the flakes prepared by passing molten silverchloride heated to 1000F. into water are not as brittle as thoseabove-described. The flakes obtained by passing molten silver chlorideat 900F. into the water are even less brittle and very difficult tohammer mill to fine particulate form, requiring an expenditure ofmilling power and energy about 300 percent more than the 1100F. to1300F. silver chloride products.

The above Examples clearly illustrate the improved results obtainedthrough the use of the present im provements in the indicated processfor preparing silver chloride. The improvements are easily and simplycarried out and result in a decrease in energy expenditure and cost ofmanufacture of particulate silver chlor ide of high purity. Otheradvantages are as set forth in the foregoing.

Various modifications, changes, alterations and additions can be made tothe present improved process, its improvements and the steps andparameters thereof. All such changes, modifications, alterations andadditions as are within the scope of the appended claims form part ofthe present invention.

What is claimed is:

1. In a process for preparing silver chloride comprising heatingmetallic silver to above the melting point of silver chloride but belowthe melting point of said silver in a reaction zone, introductingchlorine gas above said heated silver, withdrawing resulting moltensilver chloride from said reaction zone below said heated silver and,therefore, recovering solid silver chloride, the improvement whichcomprises effecting said recovery by heating said withdrawn silverchloride to at least about 1100" F. but below the decomposition pointthereof and then passing said heated silver chloride in finely dispersedliquid form into water at a temperature of at least about 1050F higherthan said water, sepa rating the resulting brittle silver chlorideflakes from said water and disintegrating said flakes to granular form.

2. The improvement of claim 1 wherein said heating of said withdrawnsilver chloride is carried out to a temperature of between about 1 F.and about 1300F.

3. The improvement of claim 2 wherein said water is at a temperature ofabout 40-60F. when said heated silver chloride initially contacts thesame by being dripped thereinto.

4. The improvement of claim 1 wherein said silver is essentially puresilver bullion, wherein said chlorine gas curvature coincides with therotational axis of the opening roller, the constraining means furtherincluding a fixed guide means slidably engaging in the channel or slotand serving to position and locate the feed pedal whereby ondisplacement of the feed pedal, cooperation between the guide means andthe channel or slot constrains the feed pedal to move in an arcuate pathwhich is concentric with the surface of the opening roller.

5. A device as claimed in claim 4 wherein the guide means comprise apair of spaced fixed pegs which are 4 a sliding fit in the channel orslot.

6. A device as claims in claim 4 wherein the guide means comprises afixed elongate arcuate spigot which is a sliding fit in the slot orrecess.

7. A device as claimed in claim 1 wherein the feed pedal includes upperand lower parts formed integrally, the said first surface being providedon the upper part and the said second surface being provided on thelower part.

8. A device as claimed in claim 1 wherein the said second surfacecomprises a planar surface extending from the feed roller towards andover the periphery of the opening roller, the planar surface lyingparallel with a tangent to the peripheral surface of the opening rollerand wherein the constraining means constrains the feed pedal to movetoward and away from the feed roller in a path parallel to the saidtangent.

9. A device as claimed in claim 8 wherein the constraining meansincludes a sliding surface parallel with said planar surface andarranged to slide along a fixed planar guide surface which is alsoparallel with the said planar surface.

10. A device as claimed in claim 8 wherein the constraining meansfurther includes a fixed spigot which slidably engages in a blind borein the feed pedal thereby serving to support and position the feedpedal.

11. A device as claimed in claim 8, wherein the feed pedal is formed asa block and wherein the said first surface is provided on an end face ofthe block and the second surface is provided on a lower face of theblock.

12. A device as claimedin claim 1 including a housing for the device,and wherein the said first surface defines with a surface of the housinga sliver feed channel which gradually converges towards the sliverforwarding nip.

13. A device as claimed in claim 1, wherein the feed pedal is biasedtowards the feed roller by a spring.

14. A device as claimed in claim 13 wherein the feed pedal includesupper and lower parts formed integrally, the said first surface beingprovided on the upper part and the said second surface being provided onsaid lower part, wherein the spring is a helical spring having one endengaging in a recess in the upper portion of the feed pedal, and havingthe other end engaging a fixed abutment.

15. A device as claimed in claim 13 including a fixed spigot whichslideably engages in a blind bore in the feed pedal, thereby serving tosupport the feed pedal, wherein the spring is a helical spring locatedin the blind bore of the feed pedal, and having one end engaging an endwall of the bore and the other end engaging the fixed spigot.

16. A device as claimed in claim 1, wherein the said first surfaceconnects with the said second surface and wherein the first surface isinclined with respect to that part at least of the said second surfacewith which it connects.

17. A device as claimed in claim 1, wherein the said first surfaceconnects with the said second surface and wherein the said first surfaceis perpendicular to that part at least of the saidsecond surface withwhich it connects.

18. A device as claimed in claim 1, wherein the said first surface isprovided with a channel extending parallel with the advance direction ofsliver fed to the feed device.

19. A device as claimed in claim 1, wherein the said second surface isprovided with a channel extending parallel with the advance direction ofthe sliver fed to the feed device.

20. A device as claimed in claim 1, wherein the peripheral surface ofthe opening roller is provided with needles or teeth.

1. A sliver feeding device for an open end spinning machine, andcomprising a feed roller, an opening roller and a displaceable feedpedal biased towards the feed roller to form between a first surface ofthe feed pedal and the peripheral surface of the feed roller a sliverforwarding nip, the feed pedal having a second surface adjacent theperipheral surface of the opening roller, and constraining meansassociated with the feed pedal to constrain the feed pedal so thatdisplacement of the feed pedal produces no substantial variation in theminimum clearance between said second surface and the peripheral surfaceof the opening roller.
 2. A device as claimed in claim 1, wherein thesaid second surface is provided with an arcuate portion which has acentre of curvature co-incident with the rotational axis of the openingroller, and wherein the feed pedal is constrained to move in an arcuatepath which is concentric with the peripheral surface of the openingroller.
 3. A device as claimed in claim 2, wherein the said secondsurface includes a planar portion extending from the feed roller towardsthe peripheral surface of the opening roller, the said planar portionlying parallel with a tangent to the peripheral surface of the openingroller and the said arcuate portion forming a continuation of the saidplanar portion.
 4. A device as claimed in claim 2, wherein theconstraining means comprises in a surface of the feed pedal transverseto said first and second surfaces, an elongate channel or slot havingarcuate sides whose centre of curvature coincides with the rotationalaxis of the opening roller, the constraining means further including afixed guide means slidably engaging in the channel or slot and servingto position and locate the feed pedal whereby on displacement of thefeed pedal, co-operation between the guide means and the channel or slotconstrains the feed pedal to move in an arcuate path which is concentricwith the surface of the opening roller.
 5. A device as claimed in claim4 wherein the guide means comprise a pair of spaced fixed pegs which area sliding fit in the channel or slot.
 6. A device as claims in claim 4wherein the guide means comprises a fixed elongate arcuate spigot whichis a sliding fit in the slot or receSs.
 7. A device as claimed in claim1 wherein the feed pedal includes upper and lower parts formedintegrally, the said first surface being provided on the upper part andthe said second surface being provided on the lower part.
 8. A device asclaimed in claim 1 wherein the said second surface comprises a planarsurface extending from the feed roller towards and over the periphery ofthe opening roller, the planar surface lying parallel with a tangent tothe peripheral surface of the opening roller and wherein theconstraining means constrains the feed pedal to move toward and awayfrom the feed roller in a path parallel to the said tangent.
 9. A deviceas claimed in claim 8 wherein the constraining means includes a slidingsurface parallel with said planar surface and arranged to slide along afixed planar guide surface which is also parallel with the said planarsurface.
 10. A device as claimed in claim 8 wherein the constrainingmeans further includes a fixed spigot which slidably engages in a blindbore in the feed pedal thereby serving to support and position the feedpedal.
 11. A device as claimed in claim 8, wherein the feed pedal isformed as a block and wherein the said first surface is provided on anend face of the block and the second surface is provided on a lower faceof the block.
 12. A device as claimed in claim 1 including a housing forthe device, and wherein the said first surface defines with a surface ofthe housing a sliver feed channel which gradually converges towards thesliver forwarding nip.
 13. A device as claimed in claim 1, wherein thefeed pedal is biased towards the feed roller by a spring.
 14. A deviceas claimed in claim 13 wherein the feed pedal includes upper and lowerparts formed integrally, the said first surface being provided on theupper part and the said second surface being provided on said lowerpart, wherein the spring is a helical spring having one end engaging ina recess in the upper portion of the feed pedal, and having the otherend engaging a fixed abutment.
 15. A device as claimed in claim 13including a fixed spigot which slideably engages in a blind bore in thefeed pedal, thereby serving to support the feed pedal, wherein thespring is a helical spring located in the blind bore of the feed pedal,and having one end engaging an end wall of the bore and the other endengaging the fixed spigot.
 16. A device as claimed in claim 1, whereinthe said first surface connects with the said second surface and whereinthe first surface is inclined with respect to that part at least of thesaid second surface with which it connects.
 17. A device as claimed inclaim 1, wherein the said first surface connects with the said secondsurface and wherein the said first surface is perpendicular to that partat least of the said second surface with which it connects.
 18. A deviceas claimed in claim 1, wherein the said first surface is provided with achannel extending parallel with the advance direction of sliver fed tothe feed device.
 19. A device as claimed in claim 1, wherein the saidsecond surface is provided with a channel extending parallel with theadvance direction of the sliver fed to the feed device.
 20. A device asclaimed in claim 1, wherein the peripheral surface of the opening rolleris provided with needles or teeth.